Asthma in Women

If you have asthma, chances are you belong to the largest demographic group currently suffering from the condition: adult women. While asthma is dramatically on the rise in men, women, and children, women alone account for more than 55 percent of the 17 million cases of asthma in the United States. From 1982 to 1992, the prevalence of asthma among American women rose 82% compared to 29% for men. The death rate from asthma for women was twice that of men. Researchers are perplexed about these statistics and are looking at treatment patterns, the environment, and basic physiology for clues to the apparent sex differences in asthma incidence and outcomes.

EPIDEMIOLOGICAL DIFFERENCES
Asthma appears to affect us differently over the course of our lives. In childhood, more boys than girls are diagnosed with asthma, and twice as many boys are admitted to the hospital for the condition. This may be due to boys having smaller airway diameters relative to lung volume, or greater allergen sensitivity. Some studies suggest girls are simply underdiagnosed. But the trend reverses beginning at puberty and by age 20 and throughout adulthood, we are nearly three times as likely as men to have the condition.

Along with noting basic differences in disease prevalence, studies cite a gender-specific bias in asthma diagnosis and treatment. Data from the National Asthma Education and Prevention Program show that women have more asthma-related hospitalizations and trips to the emergency room. Other studies suggest women may receive less aggressive asthma treatment than men. For example, corticosteroid administration, a cornerstone of effective asthma management, is often delayed in women. Because physicians are concerned about the drug's effects on pregnancy and osteoporosis, in particular, they may be less likely to prescribe such medication. This lack of treatment may inadvertently cause increased asthma severity in women.

A Canadian study showed that women tend to have significantly more severe disease and more asthma triggers and symptoms. Of 47 asthmatics admitted to an intensive care unit for near-fatal asthma, 13 were smokers. Of the 13, 11 were women. Increased use of tobacco, particularly among girls, may be one of the most significant contributors to the growth in asthma cases. While fewer women than men smoke today, it's estimated that women will smoke at the same rate as men by the end of this year.

POSSIBLE CAUSES OF ASTHMA
Although it's not clear why more new diagnoses of asthma are in women, some unique physiological factors may be at work:

Obesity. New data from the Nurses Health Study II show that obesity increases women's risk of developing adult-onset asthma. The results show clearly that the higher a woman's body-mass index (BMI), the greater her risk of developing asthma. The risk was almost three times greater for women whose BMI was 30 or more than for women whose BMI was less than 20. (A healthy BMI is considered between 19 and 25.) Epidemiological studies show the rates of asthma development parallel those of obesity.
Hormonal differences. Asthma may be related to our hormonal changes. Because rates of asthma increase in women around the time of puberty, scientists believe our sex hormones probably play an important contributory role. Up to 40% of us notice an increase in asthma symptoms immediately before or after our menstrual periods, a condition known as "perimenstrual asthma."
TREATMENT CONSIDERATIONS
Asthma is a chronic inflammatory disorder. Allergens or other stimuli cause inflammation of the airways of the lungs, which leads to constriction of bronchi and difficulty breathing. Inhaled short-acting bronchodilators or beta-agonists such as albuterol provide the fastest relief for acute asthma attacks and are effective in preventing exercise-induced asthma. Such treatments open up the airways quickly, relieving coughing, wheezing, and breathlessness. However, frequent use for persistent symptoms can cause rapid heart rates and jitters. And short-acting beta-agonists are not good for long-term symptom control because they do not treat the underlying inflammation.

Antiinflammatory drugs, particularly inhaled corticosteroids, are critical to asthma management. They suppress inflammation, decrease the hyperresponsiveness of the bronchi, and relieve symptoms. Corticosteroids taken orally (in pill form) are effective for suppressing asthma symptoms; however, their long-term use is associated with glucose intolerance, weight gain, high blood pressure, osteoporosis, and cataracts. The incidence of these complications is minor with inhaled steroids. The treatment picture may change radically within a year or two, however. A new, genetically engineered drug called rhuMAb-E25, designed to short-circuit the inflammatory response, is under study as a replacement for oral and inhaled steroids in people with moderate to severe allergic asthma.

Medications that may be taken with inhaled corticosteroids when symptoms persist include:

Salmeterol (Serevent): a long-acting beta-agonist that is used only once or twice daily.
Cromolyn sodium (Intal): inhibits mast cells involved in the inflammatory process, which underlies an asthma attack. This drug has no dilating effect on the airways, but is useful for preventing an attack in some patients.
Theophylline (Bronkodyl): an older medication that controls symptoms in some patients with persistent asthma symptoms. It is slow to act, however, and has a number of side effects that limit its use.
Leukotriene modifiers (zafirlukast, zileuton, montelukast): inhibit leukotrienes, fatty acids that mediate the inflammatory process.
OSTEOPOROSIS RISK
Long-term use of oral corticosteroids like prednisone can increase your risk of osteoporosis. Asthma patients taking as little as 7.5 mg per day of prednisone, for example, are likely to suffer some bone loss. Inhaled steroids also have dose-related side effects, including the risk of osteoporosis at high doses, but these side effects are not as severe as those associated with oral use. If you must take an oral corticosteroid, take extra steps to protect your bones. Estrogen replacement therapy (ERT) reduces osteoporosis risk in women who take oral steroids.

If you have not reached menopause or choose not to take ERT, you can take bisphosphonates to prevent and treat steroid-associated osteoporosis, particularly in the spine. Alendronate (Fosamax) was FDA-approved for this purpose last June.

Calcium and vitamin D are essential. Take 1,500 mg of calcium and 800 IU of vitamin D each day. Weightbearing physical exercise -- walking, jogging, aerobics, dancing, or weight-training--are excellent ways to strengthen bones. If your asthma is triggered by exercise, use your inhaled bronchodilator 30 minutes to an hour before exercising. If your symptoms are triggered by cold air, exercise indoors.

LIVING WITH ASTHMA
It may help to buy a peak flow meter, a small hand-held device you can use to monitor your lung function, especially if you sense an impending attack. If you have asthma, the most important thing you can do is to avoid the known triggers. And if you know you'll be exposed to an allergen, such as pollen, take your medication beforehand to avoid an attack. You may need to change your lifestyle by giving up smoking and avoiding smoky places, and you may need to keep your pets outside.

Mild Intermittent * Daytime symptoms less than or equal
to 2 times/week
* Nighttime symptoms less than or
equal to 2 times/month
* No symptoms between attacks
* Attacks brief
* Use of short-acting beta-agonist
greater than or equal to 2
times/week may indicate need for
low-dose ICS